//
// Update hosts for windows
//

package main

import (
    "os"
    "io"
    "bufio"
    "net/http"
    "time"
    "bytes"
    "io/ioutil"
)

var (
    HOSTS_PATH string = os.Getenv("SYSTEMROOT")+"\\system32\\drivers\\etc\\hosts"
    SEARCH_STRING []byte = []byte("#TX-HOSTS")
    HOSTS_SOURCE string = "http://tx.txthinking.com/hosts"
)

func main(){
    var hosts []byte
    f, err := os.OpenFile(HOSTS_PATH, os.O_RDONLY, 0444)
    if err == nil {
        bnr := bufio.NewReader(f)
        for{
            line, _, err := bnr.ReadLine()
            if bytes.Compare(line,SEARCH_STRING)==0 || err == io.EOF{
                break
            }
            hosts = append(hosts, append(line,[]byte("\r\n")...)...)
        }
        f.Close()
    }
    hosts = append(hosts, append(SEARCH_STRING,[]byte("\r\n")...)...)

    res, err := http.Get(HOSTS_SOURCE)
    if err != nil {
        println(err.Error())
        time.Sleep(3 * time.Second)
        return
    }
    data, err := ioutil.ReadAll(res.Body)
    if err != nil {
        println(err.Error())
        time.Sleep(3 * time.Second)
        return
    }
    data = bytes.Replace(data, []byte("\n"), []byte("\r\n"), -1)
    hosts = append(hosts, data...)

    os.Rename(HOSTS_PATH, HOSTS_PATH+"-BAK-TX-HOSTS")
    f, err = os.OpenFile(HOSTS_PATH, os.O_WRONLY|os.O_CREATE, 0644)
    if err != nil {
        println(err.Error())
        time.Sleep(3 * time.Second)
        return
    }
    f.Write(hosts)
    println("Success!")
    time.Sleep(3 * time.Second)
}
